The present invention relates to tarping systems for containers, such as dump bodies, transfer containers and the like. More particularly, the invention relates to the bail arms used to extend and retract the tarpaulin or cover across the open top of the container.
Tarping systems for containers, particular containers carried by a vehicle, are well-known. Two examples are shown in FIGS. 1 and 2. The transfer container 10 in FIG. 1 is carried by a truck T. Bail arms 14 carry a tarpaulin or cover 22 and are pivotably mounted to the container at a pivot mount 17 to extend the tarp across the top 12 of the container 10, with the bail arms in the extended position 14′. In one configuration, the bail arms 14 include a lower arm 15, a joint 16 and an upper arm 18 that carries a spool 20 onto which the tarp 22 is wound. In some systems, the spool is mounted on a gantry and the upper arm is connected to a cross-bar fastened to the end of the tarp. The bail arms are typically spring-driven at the pivot mount 17 for extension with a motor-driven spool for retracting the tarp.
In another container system, a dump body 25 includes a tarp 26 that extends or retracts over the open top of the dump body. One or more bail arms 27 are pivotably mounted to the container at corresponding pivot mounts 31 to carry the tarp across the dump body. The bail arms include a lower arm 28, a joint 29 and an upper arm 30 connected to the tarp 26. One or more of the bail arms may be spring-driven at the corresponding pivot mount 31 for extension or retraction, with a manual pull or a motor drive working against the spring-drive feature.
In both systems the joint 16, 29 between the lower and upper arms (15, 28 and 18, 30) is fixed, meaning that the upper arm is at a fixed angular relationship to the lower arm. This fixed relationship can be acceptable for many container sizes and configurations; however, the fixed angle does not permit flexibility in accommodating a tarping system to a particular container. For instance, the transfer container 10 shown in FIG. 1 may be shorter than depicted, or the particular fixed angle does not pull the tarp tight and relatively flat across the open top 12 of the container. Similar problems may arise with respect to the dump body of FIG. 2.